import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * @author SaoE
 * @date 2025/2/20 20:25
 */
public class _15 {
    public static List<List<Integer>> threeSum(int[] nums) {
        List<List<Integer>> res = new ArrayList<>();
        Arrays.sort(nums);
        for(int i = 0; i < nums.length; i++){
            if(nums[i] > 0){
                break;
            }
            // 关键去重
            if(i > 0 && nums[i] == nums[i-1]){
                continue;
            }
            int left = i + 1;
            int right = nums.length - 1;
            while(left < right){
                if(nums[i] + nums[left] + nums[right] == 0){
                    List<Integer> list = new ArrayList<>();
                    list.add(nums[i]);
                    list.add(nums[left]);
                    list.add(nums[right]);
                    res.add(list);
                    // 关键去重
                    while(left < right && nums[left] == nums[left+1]) {
                        left++;
                    }
                    while(left < right && nums[right] == nums[right-1]) {
                        right--;
                    }
                    left++;
                    right--;
                }else if(nums[i] + nums[left] + nums[right] < 0){
                    left++;
                }else{
                    right--;
                }
            }
        }

        return res;
    }

    public static void main(String[] args) {
        int[] nums = {-1,0,1,2,-1,-4};
        System.out.println(threeSum(nums));
    }
}
